Two emotional ceremonies were held at Police Headquarters yesterday – including the unveiling of a memorial urn to honor the 23 hero officers who died on Sept. 11.

Mayor Giuliani and Police Commissioner Bernard Kerik unveiled the urn in the lobby of One Police Plaza. It stood on a pedestal inscribed with the names of the officers who lost their lives at the Twin Towers.

“It was a very emotional and beautiful ceremony, but it was also sad,” said Ann Driscoll, whose husband, Officer Stephen Driscoll, died that day.

Immediately after that, the mayor and commissioner summoned 18 members of the department to Kerik’s office for a private awards ceremony that took the recipients totally by surprise.

Kerik gave the 18 – including First Deputy Commissioner Joseph Dunne, who retires Monday – the Medal of Valor, the department’s third-highest award, for their actions on Sept. 11.

Also among those honored were Chief of Department Joseph Esposito and Assistant Chief Thomas Fahey.

Such medals are usually awarded in September, but the outgoing mayor and police commissioner wanted to honor them while still in office.

“They were all there with me on Sept. 11, and I know the acts of heroism that each one did on that day,” Kerik said later.

Dunne was also honored yesterday by rank-and-file cops from all over the city who lined up outside the front of the building and along its sides and saluted him as he left.